[ImperialCrown]

Which engine and transaxle? The 3.0L with the 3-speed (31TH) has a mechanical kickdown linkage that can bind at the top of the transaxle underneath the battery.
The inner rod is the throttle (kickdown) shaft and the outer rod is the shifter shaft. When these 2 concentric rods bind together, you can get a hard gas pedal and shift lever movement.
Being under the battery, this area is subject to acid splash and corrosion. Sometimes they can be freed up in place or if it has corroded down the shafts, the valve body may have to come out for service or replacement.
The kickdown linkage should 'flop' freely with light return spring action to the idle position.

 

[Guest]

Yes sorry for the delay! it is in fact a 3.0 3spd auto, I cheeked the linkage under the battery and it is in fact stuck!!
I had no luck trying to solve it with Lubricant but will use power blaster next and see. I do not know how much pounding the linkage will take to free this up but am being careful, should I bang it with a mallet? I will keep trying to free it up as you advised. It is great to find a possible cure as I was shopping new used vans already thinking trans was toast, Thank you!

 

[ImperialCrown]

I soak them with a foaming graphite penetrant and try gently working the kickdown shaft. Once it starts moving continue with penetrant and exercise. Be careful about excessive force or tapping with a mallet as the shaft can shear off.
If that happens (and its happened to me), you tried your best to free it and installing a remanufactured valve body is probably the next step. The 31TH behind the 3.0L is also referred to as an A-670 transaxle.

http://www.makcotransmissionparts.com/P32740-2.html

 

[Guest]

Looks like success Imp Crown~!! Thanks very much! saved me from shipping the whole unit.
It gave my patience a test and my left arm too. It seems to be better maybe not entirely cured but close enough and perhaps it will get looser in time.
The lock out may have been ill effected in that now I need to move the shift handle in and out of park at times to get a turn over. A trade off I can live with, again. many thanks.

 

[chuzz]

You can use white vinegar to dissolve rust. Just a thought I figured I'd throw out there.

 

[ImperialCrown]

You may need to readjust the shift cable to get the starter to work consistently in Park.
I believe that both shift and kickdown shafts are aluminum?